Yale: 3 professors came to my interview and all of them are kinds of my POI although I didn't mention one in my SOP. They asked me about 1) "Who are you?", 2) "Why you want to study at Yale?", 3) "Are you going to study further on what you have done before?", 4) (For those who transfers) "What are the differences between your current program and that of Yale?", 5) "What are you planning to do after your Ph.D.?", 6) (Statistical question) "What can be erroneous if you assume causal relationship between level of education and that of income based on the result from linear regression model?" 7) (No disadvantage from this question) "Where are other universities that you applied else?", ? "Do you have anything to ask?"
-> For question #4, I just mentioned that there is somewhat mismatch between my research interests and that of my current Ph.D. program. I think question #7 is for evaluating you sincerity to the research topic so you'd better name some universities that provide your research interests.
Good luck!